Wow, clean contacts. Your photos remind me of this drawing from Williams' Introduction to Coin Operated Amusement Games (with the answers cropped out):
Williams Score Reel switches (resized).jpg
/Mark

I don't think I've run across this case. Do you have an example in mind? Extra credit if there's a schematic on IPDB for it.

Thanks,

/Mark

Hadn't noticed that before. Very interesting. Here it is for those not wanting to find the other topic:
Target Alpha Double Bonus relay coil (resized).jpg
Note that the K/Double Bonus relay coil (A-9746) apparently has a resistance of just 1.8 ohms, compared to a garden variety relay coil (e.g. A-9735) which has a resistance of 14.9 ohms. This coil would draw about (6 volts/1.8 ohms) 3.3 amps while the normal coil would draw about (25 volts/14.9 ohms) 1.6 amps or about half the current.

There's no substitute for disassembly and cleaning as @bingopodcast suggested, but if that's not your thing, mineral spirits is a great degunkifier. Apply, work the mech back and forth, apply a little more to flush out the gunk, repeat. Works well for many moving metal parts.

There is often a number of switches on one of the power rails that allow the game to do reset related things, but can cut power to game play related things. All of those switches need to be closed for the game to play. Here's an example from El Dorado:
El Dorado power (resized).jpg
Note that the Ball Count unit can control one or more of those switches, so if you don't put a ball into the game, the Outhole relay won't fire, the ball won't get kicked and close the Ball Trough switch, so the Ball Count unit won't advance and the Ball Count unit switch won't send power to the playfield.

If you're lucky you can manually advance the Ball Count unit and you might get playfield power. There could be other open switches too though.

<typo deleted>

The schematic for Gottlieb's Egg Head (another tic tac toe game) shows 23 Bank or trip relays. It's hard to confirm from the ipdb photo: https://www.ipdb.org/showpic.pl?id=758&picno=15124

Gottlieb's Sweet Sioux has a stepper with three coils. One to take a step back, one to take a step forward, and a third to step forward 2 steps.
Sweet Sioux Replay Unit coils (resized).jpg
You can barely make out all three coils in the top of the IPDB image: https://ipdb.org/showpic.pl?id=2475&picno=29390&zoom=1

That's probably not the missing 4th stepper type, but it's unusual nonetheless.

There are also Score Reels and steppers used as Alternators in some games, but they're basically continuous steppers.

/Mark

Yes I believe it's used for a "Double Match", although as far as I can tell you either get one credit per match, or 11 credits (1 plus 10 extra) per match:
Sweet Sioux Double Match (resized).jpg
When enabled, the 5 pulses from the Score Motor 1A switch fire the "Add 2 Replays" solenoid on the Replay Unit which gives you the 10 extra credits.
Thanks to www.inkochnito.nl for the adjustment card.